FILM COEFFICIENTS OF MASS TRANSFER OF DILUTE SPHERE-PACKED BEDS IN LOW FLOW RATE REGIME

Abstract

On the above subject the minimum Sherwood number is obtained by modelling a packed bed. From dimensional reasoning of the basic equations for flow of fluid and sealer transport, mass transfer process in steady Stokes flow is shown to be divided into two regimes of molecular diffusion controlling and of developing concentration boundary layer flow. The latter is observed only for liquid systems. The Sherwood number in the regimes is a sole function of the Peclet number for geometrically similar beds. By increasing the flow rate further, flow of fluid goes into the regime of developing laminar boundary layer flow, where mass transfer behaves according to the Carberry type formula. i_Dh vs. Re_h plot of gaseous film coefficients shows, for 2 ≤ Re_h ≤ 20, anomalous behaviour which depends on the magnitude of Ef. This anomaly is shown to be inherent only in dilute beds, and to come from flow transition.